Nuclear Over Hauser and Exchange Spectroscopy (NOESY) | BSc |MSc

  • It records all the proton-proton NOE’S occurring in a molecule in a single spectrum.
  • it appears like 1H – 1H COSY spectrum. where as orthogonal axis is of the proton chemical shiftand the normal spectrum appears on the diagonal.
  • NOESY is a space phenomena rather than bond interaction.
  • NOESY spectrum provides information about geometry of molecule.

For Small molecule positive NOE – enhancements are rather weak and are often examined by NOE difference spectroscopy.

For large molecules, they can give more intense NOE cross-peaks and give a wealth of information regarding their geometry.

NOE is due to the mutual dipolar relaxation of the proton.

Here ,

Large cross peaks (r) = 2.0 – 2.5 A’

Medium cross peaks ( r) = 2.0 – 2.5 A’

Small Cross peaks (r) = 2.0 – 5.0 A’

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